It had been a while since I last laid everything out like this. A few rarities in there, but mostly common pressings. My two dream purchases are a copy of Black Pear Tree, since I had one before and had to sell it, and a 12" of Full Force Galesburg (my favorite album), but I know my storage conditions aren't good enough to be spending $400 on rare vinyl.
EDIT: All that and I still forgot about my Undercard LP
I've been trying to get into more Mountain Goats but truly have no clue where to start with such a large back catalog. I've listened to The Sunset Tree, Transcendental Youth and The Jordan Lake Sessions so far.
I think those are a great foundation! The Sunset Tree is right after the transition to fully professional recording setups, so if you're into the idea of lofi at all, I would work my way backwards in time from there. If you're not so into the tape hiss thing, I'd circle back to Tallahassee and go forward from there. Either way is totally valid, and there's great stuff on every album.